Université de Bordeaux, UMR CNRS 5805 EPOC, 33615 Pessac cedex, France.
Université de Bordeaux, UMR CNRS 5805 EPOC, 33615 Pessac cedex, France.
Sci Total Environ. 2018 Feb 15;615:652-663. doi: 10.1016/j.scitotenv.2017.09.078. Epub 2017 Oct 17.
Platinum Group Elements (PGEs) are extremely scarce in the Earth's Crust and of strong interest for high-end technologies due to their specific properties. They belong to the Technology Critical Elements (TCEs) for which use is forecast to increase, implying growing emissions into the environment in the following years. In particular, with the intensive use of platinum (Pt) in car catalytic converters, the anthropogenic geochemical cycle of this element has surpassed the natural cycle. Yet, environmental Pt levels are still in the sub picomolar range, making its analytical detection a challenge. Few studies cover the behavior of Pt in marine waters in terms of speciation, reactivity and possible transfer to the biota. In this study, oysters (Crassostrea gigas) from an unpolluted estuary were exposed to the stable isotope Pt in seawater at a range of concentrations during 35days. Seawater was renewed daily and spiked to three nominal Pt concentrations (50, 100, and 10,000ng·L) for two replicate series. In addition, control conditions were monitored. Five oysters from each tank were dissected after 3, 7, 14, 21, 28, 35days of Pt exposure, and analyzed by ICP-MS. Accuracy of this analytical method applied to biological matrix was checked by an inter-method comparison with a voltammetrical technique. A concentration-dependent accumulation of Pt in oysters increasing with exposure time occurred. After 28days, oyster Pt accumulation from low and intermediate exposure conditions reached a plateau. This was not the case of the highest exposure condition for which oyster tissues showed increasing concentrations until the last day of the experiment. A linear correlation exists between seawater concentrations and Pt content in oysters for low and intermediate exposure concentrations i.e. closer to environmental concentrations. By showing high Pt accumulation potential, oysters may serve as sentinels, ensuring biomonitoring of Pt concentrations in marine coastal waters.
铂族元素（PGEs）在地壳中极为稀缺，由于其特殊性质，它们是高科技领域的重要元素。它们属于技术关键元素（TCEs），预计其使用量将增加，这意味着未来几年环境中的排放量将增加。特别是由于汽车催化转化器中大量使用铂（Pt），该元素的人为地球化学循环已经超过了自然循环。然而，环境中的 Pt 水平仍处于亚皮摩尔范围内，这使得其分析检测具有挑战性。很少有研究涉及 Pt 在海洋水中的形态、反应性和可能向生物群转移的行为。在这项研究中，来自未受污染河口的牡蛎（Crassostrea gigas）在 35 天内暴露于海水中一系列浓度的稳定同位素 Pt 中。每天更换海水，并向两个重复系列的三个名义 Pt 浓度（50、100 和 10,000ng·L）中添加。此外，还监测了对照条件。在 Pt 暴露 3、7、14、21、28 和 35 天后，从每个水槽中取出 5 个牡蛎进行解剖，并通过 ICP-MS 进行分析。通过与伏安技术的方法间比较来检查该分析方法应用于生物基质的准确性。Pt 在牡蛎中的积累随暴露时间呈浓度依赖性增加。在 28 天后，低和中等暴露条件下牡蛎的 Pt 积累达到了一个平台。在最高暴露条件下则不是这种情况，因为在实验的最后一天，牡蛎组织中的浓度仍在增加。对于低和中等暴露浓度，即更接近环境浓度的海水浓度与牡蛎中 Pt 含量之间存在线性相关。牡蛎具有较高的 Pt 积累潜力，可用作哨兵，确保对海洋沿海水域中 Pt 浓度进行生物监测。
